The present invention relates to drive controls for torque motors used particularly to drive reelers, rollers, conveyors, presses and the like, with operator adjustable tension (torque) control.
D.C. shunt wound motors driven off a 115V, 60 cycle single phase A.C. line, have long been used for such purposes and tension (torque) control has been provided by a field circuit comprising a variable autotransformer to change field strength and a rectifier. Variable autotransformers have also been used in armature circuits.
It is an important object of the present invention to eliminate the cost and bulk of the variable autotransformer while providing control conditions consistent with a tolerance of a captive load which varies by a factor of 4-5.times. and simple circuitry and low cost.